University of Illinois at Chicago College of Nursing, 845 S. Damen Ave., 9th Floor, Chicago, IL 60612, USA.
Pennsylvania State University, Department of Sociology and Criminology, Department of Anthropology, and Popualtion Research Institute, 211 Oswald Tower, University Park, PA 16802-6211, USA.
Health Place. 2018 May;51:52-60. doi: 10.1016/j.healthplace.2018.02.004.
This study examined the number of days of global positioning system (GPS) monitoring needed to measure attributes of an individual's routine activity space. Multiple alternative activity space representations (cumulative, mean daily), measures (kernel density, route buffer, convex hull), and attributes (area size, supermarkets, fast food restaurants, parks) were examined. Results suggested wide variability in required GPS days to obtain valid estimates of activity space attributes (1-23 days). In general, fewer days were needed for mean daily activity space representations, kernel density measures, and densities of environmental exposures (vs. counts). While kernel density measures reliably estimated between-person differences in attributes after just a few days, most variability in environmental attributes for convex hull and route buffer measures was within-person. Based on these results, a minimum of 14 days of valid GPS data is recommended to measure activity spaces.
本研究旨在探讨全球定位系统 (GPS) 监测所需的天数，以测量个体日常活动空间的属性。本研究还检验了多种替代的活动空间表示方法（累积法、平均每日法）、度量方法（核密度法、路径缓冲区法、凸包法）和属性（面积大小、超市、快餐店、公园）。结果表明，要获得活动空间属性的有效估计值，GPS 天数的差异很大（1-23 天）。一般来说，对于平均每日活动空间表示法、核密度度量法和环境暴露密度（与计数相比），所需的天数更少。虽然核密度度量法在仅几天的时间内就能可靠地估计属性的个体间差异，但对于凸包和路径缓冲区度量法，环境属性的大多数差异都是个体内的。基于这些结果，建议至少需要 14 天有效的 GPS 数据来测量活动空间。
